The Management and Prevention of Anal Squamous Cell Carcinoma

Unraveling Emerging Anal Cancer Clinical Biomarkers from Current Immuno-Oncogenomics Advances

Anal squamous cell carcinoma (ASCC) is a rare gastrointestinal malignancy associated with high-risk human papillomavirus (HPV) and is currently one of the fastest-growing causes of cancer incidence and mortality in developed countries. Although next-generation sequencing technologies (NGS) have revolutionized cancer and immuno-genomic research in various tumor types, a limited amount of clinical research has been developed to investigate the expression and the functional characterization of genomic data in ASCC. Herein, we comprehensively assess recent advancements in "omics" research, including a systematic analysis of genome-based studies, aiming to identify the most relevant ASCC cancer driver gene expressions and their associated signaling pathways. We also highlight the most significant biomarkers associated with anal cancer progression, gene expression of potential diagnostic biomarkers, expression of therapeutic drug targets, and emerging treatment opportunities. This review stresses the urgent need for developing target-specific therapies in ASCC. By illuminating the molecular characteristics and drug-target expression in ASCC, this study aims to provide insights for the development of precision medicine in anal cancer.

Pathogenic alterations in PIK3CA and KMT2C are frequent and independent prognostic factors in anal squamous cell carcinoma treated with salvage abdominoperineal resection

The management of anal squamous cell carcinoma (ASCC) has yet to experience the transformative impact of precision medicine. Conducting genomic analyses may uncover novel prognostic biomarkers and offer potential directions for the development of targeted therapies. To that end, we assessed the prognostic and theragnostic implications of pathogenic variants identified in 571 cancer-related genes from surgical samples collected from a homogeneous, multicentric French cohort of 158 ASCC patients who underwent abdominoperineal resection treatment. Alterations in PI3K/AKT/mTOR, chromatin remodeling, and Notch pathways were frequent in HPV-positive tumors, while HPV-negative tumors often harbored variants in cell cycle regulation and genome integrity maintenance genes (e.g., frequent TP53 and TERT promoter mutations). In patients with HPV-positive tumors, KMT2C and PIK3CA exon 9/20 pathogenic variants were associated with worse overall survival in multivariate analysis (Hazard ratio (HR)KMT2C  = 2.54, 95%CI = [1.25,5.17], P value = .010; HRPIK3CA  = 2.43, 95%CI = [1.3,4.56], P value = .006). Alterations with theragnostic value in another cancer type was detected in 43% of patients. These results suggest that PIK3CA and KMT2C pathogenic variants are independent prognostic factors in patients with ASCC with HPV-positive tumors treated by abdominoperineal resection. And, importantly, the high prevalence of alterations bearing potential theragnostic value strongly supports the use of genomic profiling to allow patient enrollment in precision medicine clinical trials.

Analysis of definitive chemo-radiation outcomes in anal cancer: insights from a tertiary cancer center in the MENA Region

Background

Outcomes of chemo-radiation (CRT) for anal cancer in Middle East and North Africa (MENA) are scarce. We aim to report treatment outcomes for anal cancer treated at tertiary cancer center, with a particular focus on patients managed with non-oncological surgery prior definitive CRT.

Methods

We conducted a retrospective review of patients diagnosed with locally advanced anal carcinoma, who underwent definitive CRT King Hussein Cancer Center, from January 2007 till January 2020. Patient demographics and disease characteristics were extracted, and a univariate chi-squared test was employed to assess the impact of chemotherapy type, HPV status, and pre-treatment non-oncological surgery on outcomes, including complete remission (CR), disease-free survival (DFS), and overall survival (OS). Kaplan-Meier tests were employed to analyze the obtained survival data.

Results

Among the 34 initially identified patients, 30 were eligible, 24 (80%) achieved CR. Notably, 20 out of 21 HPV positive patients achieved CR, versus 1 out 4 HPV-negative achieved CR, p=0.006The 5-years OS for HPV-positive patients was 89% compared with 25% for HPV-negative, p=0001. There was no statistical significant difference in patients outcomes as regard type of chemotherapy, radiation technique and non-oncologic resection prior to CRT.

Conclusion

Herein, we reported the first series of anal cancer from our region. CRT had yielded an oncologic outcome comparable with series in the literature. HPV-positive patients demonstrated better results. Moreover, we found non-oncologic resection prior to CRT did not seem to impact the outcomes. Further studies are warranted to overcome the limitations of our study.

Using Tumor-Informed Circulating Tumor DNA (ctDNA)-Based Testing for Patients with Anal Squamous Cell Carcinoma

BACKGROUND

Anal squamous cell carcinoma (SCCA) is an uncommon malignancy with a rising incidence that has a high cure rate in its early stages. There is an unmet need for a reliable method to monitor response to treatment and assist in surveillance. Circulating tumor DNA (ctDNA) testing has shown great promise in other solid tumors for monitoring disease progression and detecting relapse in real time. This study aimed to determine the feasibility and use of personalized and tumor-informed ctDNA testing in SCCA.

PATIENTS AND METHODS

We analyzed real-world data from 251 patients (817 plasma samples) with stages I-IV SCCA, collected between 11/5/19 and 5/31/22. The tumor genomic landscape and feasibility of ctDNA testing was examined for all patients. The prognostic value of longitudinal ctDNA testing was assessed in patients with clinical follow-up (N = 37).

RESULTS

Whole-exome sequencing analysis revealed PIK3CA as the most commonly mutated gene, and no associations between mutations and stage. Anytime ctDNA positivity and higher ctDNA levels (MTM/mL) were associated with metastatic disease (P = .004). For 37 patients with clinical follow-up, median follow-up time was 21.0 months (range: 4.1-67.3) post-diagnosis. For patients with stages I-III disease, anytime ctDNA-positivity after definitive treatment was associated with reduced DFS (HR: 28.0; P = .005).

CONCLUSIONS

Our study demonstrates the feasibility of personalized and tumor-informed ctDNA testing as an adjunctive tool in patients with SCCA as well as potential use for detection of molecular/minuteimal residual disease, and relapse during surveillance. Prospective studies are needed to better evaluate the use of ctDNA testing in this indication.

Prognostic Factors of Long-Term Outcomes after Primary Chemo-Radiotherapy in Non-Metastatic Anal Squamous Cell Carcinoma: An International Bicentric Cohort

Anal squamous cell carcinoma (ASCC) is a rare malignancy with a rising incidence associated with human papillomavirus (HPV) infection. The locally advanced disease is associated with a 30% rate of treatment failure after standard chemoradiotherapy (CRT). We aimed to elucidate the prognostic factors for ASCC after curative CRT. A retrospective multicenter study of 176 consecutive patients with ASCC having completed CRT treated between 2010 and 2017 at two centers was performed. Complete response (CR), disease-free survival (DFS), and overall survival (OS) were analyzed by Kaplan–Meier estimates with log-rank tests. The hierarchical clustering on principal components (HCPC) method was employed in an unsupervised and multivariate approach. The CR rate was 70% and was predictive of DFS (p < 0.0001) and OS (p < 0.0001), where non-CR cases were associated with shorter DFS (HR = 16.5, 95% CI 8.19–33.21) and OS (HR = 8.42, 95% CI 3.77–18.81) in a univariate analysis. The median follow-up was 38 months, with a 3-year DFS of 71%. The prognostic factors for DFS were cT1-T2 (p = 0.0002), N0 (p = 0.035), HIV-positive (p = 0.047), HIV-HPV coinfection (p = 0.018), and well-differentiated tumors (p = 0.037). The three-year OS was 81.6%. Female sex (p = 0.05), cT1-T2 (p = 0.02) and well-differentiated tumors (p = 0.003) were associated with better OS. The unsupervised analysis demonstrated a clear segregation of patients in three clusters, identifying that poor prognosis clusters associated with shorter DFS (HR = 1.74 95% CI = 1.25–2.42, p = 0.0008) were enriched with the locally advanced disease, anal canal location, HIV-HPV coinfection, and non-CR. In conclusion, our results reinforce the prognostic value of T stage, N stage, sex, differentiation status, tumor location, and HIV-HPV coinfection in ASCC after CRT.

Parallel-Group Controlled Trial of Surgery Versus Chemoradiotherapy in Patients With Stage I Esophageal Squamous Cell Carcinoma

BACKGROUND & AIMS

Surgery is the standard of care for T1bN0M0 esophageal squamous cell carcinoma (ESCC), whereas chemoradiotherapy (CRT) is a treatment option. This trial aimed to investigate the noninferiority of CRT relative to surgery for T1bN0M0 ESCC.

METHODS

Clinical T1bN0M0 ESCC patients were eligible for enrollment in this prospective nonrandomized controlled study of surgery versus CRT. The primary endpoint was overall survival, which was determined using inverse probability weighting with propensity scoring. Surgery consisted of an esophagectomy with 2- or 3-field lymph node dissection. CRT consisted of 2 courses of 5-fluorouracil (700 mg/m²) on days 1-4 and cisplatin (70 mg/m²) on day 1 every 4 weeks with concurrent radiation (60 Gy).

RESULTS

From December 20, 2006 to February 5, 2013, a total of 368 patients were enrolled in the nonrandomized portion of the study. The patient characteristics in surgery arm and CRT arm, respectively, were as follows: median age, 62 and 65 years; proportion of males, 82.8% and 88.1%; and proportion of performance status 0, 99.5% and 98.1%. Comparisons were made using the nonrandomized groups. The 5-year overall survival rate was 86.5% in the surgery arm and 85.5% in the CRT arm (adjusted hazard ratio, 1.05; 95% confidence interval, 0.67-1.64 [<1.78]). The complete response rate in the CRT arm was 87.3% (95% confidence interval, 81.1-92.1). The 5-year progression-free survival rate was 81.7% in the surgery arm and 71.6% in the CRT arm. Treatment-related deaths occurred in 2 patients in the surgery arm and none in the CRT arm.

CONCLUSIONS

CRT is noninferior to surgery and should be considered for the treatment of T1bN0M0 ESCC.

Prevention and Screening of HPV Malignancies

It is estimated that 5% of the global cancer burden, or approximately 690,000 cancer cases annually, is attributable to human papillomavirus (HPV). Primary prevention through prophylactic vaccination is the best option for reducing the burden of HPV-related cancers. Most high-income countries (HICs) have introduced the HPV vaccine and are routinely vaccinating adolescent boys and girls. Unfortunately, although they suffer the greatest morbidity and mortality due to HPV-related cancers, many lower- and middle-income countries (LMICs) have been unable to initiate and sustain vaccination programs. Secondary prevention in the form of screening has led to substantial declines in cervical cancer incidence in areas with established screening programs, but LMICs with absent or inadequate screening programs have high incidence rates. Meanwhile, HICs have seen incidence rates of anal and oropharyngeal cancers rise owing to the limited availability of organized screening for anal cancer and no validated screening options for oropharyngeal cancer. The implementation of screening programs for individuals at high risk of these cancers has the potential to reduce the burden of cervical cancer in LMICs, of anal and oropharyngeal cancers in HICs, and of anal cancer for highly selected HIV+ populations in LMICs. This review will discuss primary prevention of HPV-related cancers through vaccination and secondary prevention through screening of cervical, anal, and oropharyngeal cancers. Areas of concern and highlights of successes already achieved are included.

Radiotherapy alone versus chemoradiotherapy for stage I anal squamous cell carcinoma: a systematic review and meta-analysis

PURPOSE

Patients with stage I anal squamous cell carcinoma (SCC) have been underrepresented in landmark trials showing superiority of chemoradiotherapy over radiotherapy for definitive treatment. This review aims to elucidate whether definitive treatment with radiotherapy versus chemoradiotherapy is associated with differences in survival and treatment-related toxicity outcomes in patients with stage I anal SCC.

METHODS

Medline, EMBASE, and CENTRAL were searched as of November 2020 to identify studies comparing outcomes of radiotherapy versus chemoradiotherapy for non-operative treatment of patients with stage I anal SCC. The primary outcomes were 5-year overall survival and 5-year disease-free survival. The secondary outcome was treatment-related toxicities. A pairwise meta-analysis was performed using an inverse-variance random-effects model.

RESULTS

From 2174 citations, 5 retrospective studies with 415 patients treated with radiotherapy and 3784 patients treated with chemoradiotherapy were included. Patients treated with chemoradiotherapy had an increased 5-year overall survival (RR 1.18, 95% CI 1.10-1.26, p < 0.00001, I² = 0%) but no significant difference in 5-year disease-free survival (RR 1.01, 95% CI 0.92-1.11, p = 0.87, I² = 0%). Treatment-related toxicities could not be meta-analyzed due to heterogeneity. Limited data from individual studies suggested an increased frequency of select toxicities with chemoradiotherapy.

CONCLUSION

Radiotherapy may be an appropriate alternative to chemoradiotherapy for patients with stage I anal SCC who may be unable to tolerate chemotherapy-related toxicity; however, chemoradiotherapy remains the gold standard. Larger prospective studies comparing strategies for this select patient population are needed to clarify whether treatment can be de-escalated.

Anal squamous cell carcinoma: a retrospective case series

BACKGROUND

Anal cancer is a relatively rare cancer with 660 cases diagnosed in 2000-2015 in Ireland (1). The current standard treatment is radical chemoradiotherapy (CRT). The aim of our study was to review the treatment and outcomes of patients with localised anal squamous cell carcinoma (SCC), who received radical treatment in our radiation oncology network between 2008 and 2014 inclusive.

METHODS

Data were collected retrospectively from ARIA® oncology information system and patient charts. Statistical analyses were performed using IBM® SPSS® statistical software version 25.0.

RESULTS

Seventy-nine cases of anal SCC were identified. Mean age of patients at commencement of radiotherapy (RT) was 60.2 years (standard deviation: 13.1 years). The most common total RT dose was 50.4 Gy in 28 fractions (N = 58; 73.4%). Median follow-up was 5.6 years. Two (2.6%) patients had persistent disease, seventeen (21.8%) patients developed loco-regional recurrence and nine (11.5%) patients developed solid organ metastases, four of whom had complete treatment response at the primary site. Eight patients underwent salvage anal surgery following completion of RT. Median overall survival was 10.5 years (95% confidence interval (CI) 5.1-15.8 years), median loco-regional relapse-free survival was 10.4 years (95% CI 4.4-16.3 years) and median disease-free survival was 9.3 years (95% CI 6.3-12.2 years).

CONCLUSION

Our study demonstrates that treatment for anal SCC and outcomes following definitive CRT in Ireland during the study period were comparable to international standards.

Factors Associated With Chemoradiation Therapy Interruption and Noncompletion Among Patients With Squamous Cell Anal Carcinoma

Importance

Definitive chemoradiation for anal cancer is effective but may be associated with toxic effects, and some patients may not be able to complete the planned treatment. Identifying factors associated with treatment interruption and noncompletion is important to target quality improvement efforts.

Objective

To identify rates of chemoradiation treatment interruption or noncompletion and factors associated with this among patients with anal cancer treated in routine clinical practice.

Design, Setting, and Participants

In this population-based, retrospective cohort study, the Ontario Cancer Registry was used to identify all incident cases of squamous cell anal cancer treated with curative-intent radiation from 2007 to 2015 in Ontario, Canada. Final analysis of data was performed on August 9, 2019.

Exposures

Curative-intent radiation therapy.

Main Outcomes and Measures

Treatment interruption was defined as more than 7 days between fractions of radiation. Radiation completion was defined as receipt of 45 Gy or more and 25 fractions of radiation. Chemoradiation completion was defined as radiation completion and 2 doses of combination chemotherapy. Associations between patient factors and treatment interruption and noncompletion were estimated with log-binomial models. Cox proportional hazard models were used to estimate the association of treatment interruption or noncompletion with all-cause death, cancer-specific death, and the combined outcome of colostomy or death.

Results

Overall, 1125 patients with stage I-III anal cancer were treated with curative-intent radiation. Treatment interruptions occurred in 262 (23%). Radiation and chemoradiation noncompletion occurred in 199 (18%) and 280 (25%), respectively. No associations were found to correlate with an increased risk of treatment interruption. Patients older than 70 years were less likely to complete chemoradiation (risk ratio [RR], 0.60; 95% CI, 0.52-0.70), compared with those younger than 50 years. Patients with a higher number of comorbidities were also less likely to complete chemoradiation (RR, 0.70; 95% CI, 0.51-0.95). Patients who did not complete chemoradiation had a higher risk of requiring salvage abdominoperineal resection (RR, 1.54; 95% CI, 1.03, 2.31), overall death (hazard ratio [HR], 1.54; 95% CI, 1.23-1.92), cancer-specific death (HR, 1.59; 95% CI, 1.14-2.22), and colostomy or death (HR, 1.80; 95% CI: 1.10-2.93). Treatment interruptions longer than 7 days were not associated with death.

Conclusions and Relevance

Many patients undergoing curative-intent chemoradiation for anal cancer experienced treatment interruption or noncompletion. Quality improvement initiatives to optimize treatment continuity and completion are needed.